Multi-layered polymer structure for medical products

ABSTRACT

A multiple layer structure comprising a skin layer composed of a polypropylene copolymer with styrene ethylene-butene styrene block copolymer within a range of 0-20% by weight skin layer, and, a radio frequency (&#34;RF&#34;) susceptible layer adhered to the skin layer. The RF layer has a first component of a propylene based polymer, a second component of a nonpropylene polyolefin, a third component of a radio frequency susceptible polymer, and a fourth component of a polymeric compatibilizing agent.

DESCRIPTION

1. Technical Field

The present invention relates generally to materials for making medicalgrade products and more specifically to a film product which may be usedto manufacture articles such as plastic containers for sterile fluids,blood component storage containers, cell product containers, and thelike.

2. Background Prior Art

In the medical field, where beneficial agents are collected, processedand stored in containers, transported, and ultimately delivered throughtubes by infusion to patients to achieve therapeutic effects, materialswhich are used to fabricate the containers must have a uniquecombination of properties. For example, in order to visually inspectsolutions for particulate contaminants, the container must be opticallytransparent. To infuse a solution from a container by collapsing thecontainer walls, without introducing air into the container, thematerial which forms the walls must be sufficiently flexible. Thematerial must be functional over a wide range of temperatures. Thematerial must function at low temperatures by maintaining itsflexibility and toughness because some solutions, for example, certainpremixed drug solutions are stored and transported in containers attemperatures such as -25 to -30° C. to minimize the drug degradation.The material must also be functional at high temperatures to withstandthe heat of sterilization; a process which most medical packages andnutritional products are subjected to prior to shipment. Thesterilization process usually includes exposing the container to steamat temperatures typically 121° C. and at elevated pressures. Thus, thematerial needs to withstand the temperature and pressures withoutsignificant distortions ("heat distortion resistance").

For ease of manufacture into useful articles, it is desirable that thematerial be sealable using radio frequency ("RF") generally at about27.12 MHz. Therefore, the material should possess sufficient dielectricloss properties to convert the RF energy to thermal energy.

A further requirement is to minimize the environmental impact upon thedisposal of the article fabricated from the material after its intendeduse. For those articles that are disposed of in landfills, it isdesirable to use as little material as possible and avoid theincorporation of low molecular weight leachable components to constructthe article. Thus, the material should be light weight and have goodmechanical strength. Further benefits are realized by using a materialwhich may be recycled by thermoplastically reprocessing thepost-consumer article into other useful articles.

For those containers which are disposed of through incineration, it isnecessary to use a material which helps to eliminate the dangers ofbiological hazards, and to minimize or eliminate entirely the formationof inorganic acids which are environmentally harmful, irritating, andcorrosive, or other products which are harmful, irritating, or otherwiseobjectionable upon incineration.

It is also desirable that the material be free from or have a lowcontent of low molecular weight additives such as plasticizers,stabilizers and the like which could be released into the medications orbiological fluids or tissues thereby causing danger to patients usingsuch devices or are contaminating such substances being stored orprocessed in such devices. For containers which hold solutions fortransfusion, such contamination could make its way into the transfusionpathway and into the patient causing harm to the patient.

Traditional flexible polyvinyl chloride materials meets a number of, andin some cases, most of the above-mentioned requirements. Polyvinylchloride ("PVC") also offers the distinct advantage of being one of themost cost effective materials for constructing devices which meet theabove requirements. However, PVC may generate objectionable amounts ofhydrogen chloride (or hydrochloric acid when contacted with water) uponincineration, causing corrosion of the incinerator. PVC sometimescontains plasticizers which may leach into drugs or biological fluids ortissues that come in contact with PVC formulations. Thus, many materialshave been devised to replace PVC. However, most alternate materials aretoo expensive to implement and still do not meet all of the aboverequirements.

There have been many attempts to develop a film material to replace PVC,but most attempts have been unsuccessful for one reason or another. Forexample, in U.S. Pat. No. 4,966,795 which discloses multi-layer filmcompositions capable of withstanding the steam sterilization, cannot bewelded by radio frequency dielectric heating thus cannot be assembled bythis rapid, low cost, reliable and practical process. EuropeanApplication No. EP 0 310 143 A1 discloses multilayer films that meetmost of the requirements, and can be RF welded. However, components ofthe disclosed film are cross-linked by radiation and, therefore, cannotbe recycled by the standard thermoplastic processing methods. Inaddition, due to the irradiation step, appreciable amounts of aceticacid is liberated and trapped in the material. Upon steam sterilization,the acetic acid migrates into the packaging contents as a contaminantand by altering the pH of the contents acts as a potential chemicalreactant to the contents or as a catalyst to the degradation of thecontents.

The main objective of the present invention is the creation ofthermoplastic materials which are, overall, superior to those materials,of which we are aware, which have been heretofore known to the art orhave been commercially used or marketed. The properties of suchmaterials includes flexibility, extensibility, and strainrecoverability, not just at room temperatures, but through a wide rangeof ambient and refrigerated temperatures. The material should besufficiently optically transparent for visual inspection, and steamsterilizable at temperatures up to 121° C. The material should becapable of being subjected to significant strains without exhibitingstrain whitening, which can indicate a physical and a cosmetic defect. Afurther objective is that the material be capable of assembly by the RFmethods. Another objective is that the material be substantially free oflow molecular weight leachable additives, and be capable of safedisposal by incineration without the generation of significant amountsof corrosive inorganic acids. Another objective is that the material berecyclable by standard thermoplastic processing methods after use. It isalso desirable that the material incorporate reground scrap materialrecovered during the manufacturing process to reduce material costs andreduce manufacturing waste. Finally, the material should serve as a costeffective alternative to various PVC formulations currently being usedfor medical devices.

When more than one polymer is blended to form an alloying composition,it is difficult to achieve all of the above objectives simultaneously.For example, in most instances alloy compositions may scatter light;thus, they fail to meet the optical clarity objective. The lightscattering intensity (measured by haze) depends on the domain size ofcomponents in the micrometer (μ) range, and the proximity of therefractive indices of the components. As a general rule, the selectionof components that can be satisfactorily processed into very smalldomain sizes, and yet with a minimum of refractive index mismatches, isa difficult task.

The present invention is provided to solve these and other problems.

SUMMARY OF THE INVENTION

In accordance with the present invention certain multiple layer polymerbased structures such as films are disclosed. The films may befabricated into medical grade articles such as containers for storingmedical solutions or blood products, blood bags, and related items, orother products constructed from multi-layered structures.

It is an object of the present invention to prepare a multi-layered filmhaving the following physical properties: (1) a mechanical modulus lessthan 40,000 psi and more preferably less than 25,000 psi when measuredin accordance with ASTM D-882, (2) a greater than or equal to 70%, andmore preferably greater than or equal to 75%, recovery in length afteran initial deformation of 20%, (3) and optical haze of less than 30%,and more preferably less than 15%, when measured for a composition 9mils thick and in accordance to ASTM D-1003, (4) the loss tangentmeasured at 1 Hz at processing temperatures is greater than 1.0, andmore preferably greater than 2.0, (5) the content of elemental halogensis less than 0.1%, and more preferably less than 0.01%, (6) the lowmolecular weight water soluble fraction is less than 0.1%, and morepreferably less than 0.005%, (7) the maximum dielectric loss between 1and 60 MHz and between the temperature range of 25-250° C. is greaterthan or equal to 0.05 and more preferably greater than or equal to 0.1,(8) autoclave resistance measured by sample creep at 121° C. under 27psi loading is less than or equal to 60% and more preferably less thanor equal to 20%, and (9) there is no strain whitening after beingstrained at moderate speeds of about 20 inches (50 cm) per minute atabout 100% elongation and the presence of strain whitening is noted orthe lack thereof.

The multiple layer structure of the present invention comprises a skinlayer preferably composed of polypropylene copolymers with styrene andhydrocarbon block copolymers. More preferably a propylene copolymer withethylene-butene styrene ("SEBS") within a range of 0-20% by weight ofthe skin layer. The structure further includes a radio frequency ("RF")susceptible layer adhered to the skin layer. The RF layer is composed ofa first component of a polypropylene polymer, a second component of anonpropylene polyolefin (one that does not contain propylene repeatingunits), a third component of a radio frequency susceptible polymer, anda fourth component of a polymeric compatibilizing agent. In alternateembodiments, additional layers such as core, scrap, and barrier layersare added to the skin and RF layers to confer additional or enhancedfunctionality of the resultant film structure.

The RF layer is the subject of the concurrently filed U.S. patent Ser.No. 08/153,823, U.S. Pat. No. 5,686,527 which is incorporated herein byreference. The multi-layered film structure of the present inventionoffers additional features that the compositions of the RF layer alonedo not provide. The additional features of the multi-layer film includean exterior surface gloss and reduced tackiness to the outside surfaceof the film structure. Additionally, the multilayered film structure hasimproved vapor barrier properties, greater strength and optical clarity,and is cleaner or has reduced tendency to migrate into the contents ofthe container.

The core layer, which is interposed between the skin layer and the RFlayer consists of three components. Preferably, the first component ispolypropylene which constitutes about 40% of the core layer, the secondcomponent is an ultra low density polyethylene ("ULDPE") whichconstitutes about 50% by weight of the core layer, and the thirdcomponent is styrene-hydrocarbon block copolymer and more preferably anSEBS block copolymer which constitutes about 10% by weight of the corelayer. The entire core layer should be 4.0 mils thick.

It is also desirable, for economic reasons among others, to incorporatereground scrap material recovered during the processing of the filmmaterial back into the composition of a film structure. This can lead tousing significant amount of scrap material as a weight percent of theentire layer structure, thereby substantially decreasing the costs ofthe film product. The reground scrap may be incorporated into theabove-described structure either as an additional discrete layer locatedsomewhere between the skin layer and the RF layer or may be blended intothe core layer as an additional component. In either case, significantresources are saved by reprocessing the scrap material.

To increase gas barrier properties of the structure, it is desirable toincorporate a barrier layer between the skin layer and the RF layer. Thebarrier layer may be attached to surrounding layers using adhesive tielayers. The barrier layer may be selected from ethylene vinyl alcoholssuch as that sold under the name Evalca (EVALCA Co.), highly glassy orcrystalline polyamide such as SCLAR PA® (Dupont Chemical Co.), highnitrile content acrylonitrile copolymers such as those sold under thetradename BAREX® sold by British Petroleum.

Films having the aforesaid structure and compositions have been found tobe flexible, optically clear, non-strain whitening, and steam andradiation sterilizable. Additionally, the films are compatible withmedical applications because the components which constitute the filmhave a minimal extractability to the fluids and contents that thecomposition come in contact with. Further, the films are environmentallysound in that they do not generate harmful degradants upon incineration.Finally, the films provide a cost effective alternative to PVC.

Additional features and advantages of the present invention aredescribed in, and will be apparent from, the drawing and the detaileddescription of the presently preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-sectional view of a two layered film structure ofthe present invention;

FIG. 2 shows a cross-sectional view of a three layered film structure ofthe present invention including a core layer added to the film of FIG.1;

FIG. 3 shows a cross-sectional view of the film of FIG. 1 with asolution contact layer;

FIG. 4 shows a cross-sectional view of a four layered structure of thepresent invention having a discrete layer of scrap material between theskin and the core layers;

FIG. 5 shows a cross-sectional view of a film structure using regroundscrap as a discrete layer between the core and the RF layers;

FIG. 6 shows a cross-sectional view of a film structure using regroundscrap as a discrete layer which splits the core layer into two corelayers;

FIG. 7 shows a cross-sectional view of a film structure of the presentinvention having seven layers including a barrier layer between the coreand the RF layers and two tie layers;

FIG. 8 shows the same structure of FIG. 6 except the barrier layer isdisposed between the core layer and the skin layers;

FIG. 9 shows a cross-sectional view of a film structure having a barrierlayer dividing the core layers; and,

FIG. 10 shows a container constructed from one of the film structures ofthe present invention.

DETAILED DESCRIPTION

While this invention is susceptible of embodiments in many differentforms, and will herein be described in detail, preferred embodiments ofthe invention are disclosed with the understanding that the presentdisclosure is to be considered as exemplifications of the principles ofthe invention and are not intended to limit the broad aspects of theinvention to the embodiments illustrated.

According to the present invention, multiple layered film structures areprovided which meet the requirements set forth above.

FIG. 1 shows a two layered film structure 10 having a skin layer 12 anda radio frequency ("RF") susceptible layer 14. The skin layer 12 confersheat distortion resistance and abrasion resistance and is preferably apolypropylene and more preferably a polypropylene copolymer blended withstyrene and hydrocarbon block copolymers. More preferably, the skinlayer 12 is a polypropylene copolymer blended with SEBS block copolymerwithin a range of 0-20% by weight. The skin layer 12 should have athickness within the range of 0.2-3.0 mils thick.

The RF susceptible layer 14 of the present invention should have adielectric loss of greater than 0.05 at frequencies within the range of1-60 MHz within a temperature range of ambient to 250° C. The RF layer14 preferably has four components. The RF layer 14 confers RFsealability, flexibility, heat distortion resistance, and compatibilityto the film structure 10. The first component of the RF layer 14 ischosen from polypropylene copolymers and preferably the propylenealpha-olefin random copolymers ("PPE"). The PPE's possess the requiredrigidity and the resistance to yielding at the autoclave temperatures ofabout 121° C. However, by themselves, the PPE's are too rigid to meetthe flexibility requirements. When combined by alloying with certain lowmodulus polymers, good flexibility can be achieved.

These low modulus copolymers can include ethylene based copolymers suchas ethylene-co-vinyl acetate ("EVA"), ethylene co-alpha olefins, or theso-called ultra low density (typically less than 0.90 Kg/L)polyethylenes ("ULDPE"). These ULDPE include those commerciallyavailable products sold under the trademarks TAFMER® (MitsuiPetrochemical Co.) under the product designation A485, EXACT® (ExxonChemical Company) under the product designations 4023-4024, and INSITE®technology polymers (Dow Chemical Co.). In addition, poly butene-l("PB"), such as those sold by Shell Chemical Company under productdesignations PB-8010, PB-8310; thermoplastic elastomers based on SEBSblock copolymers, (Shell Chemical Company), poly isobutene ("PIB") underthe product designations VISTANEX L-80, L-100, L-120, L-140 (ExxonChemical Company), ethylene alkyl acrylate, the methyl acrylatecopolymers ("EMA") such as those under the product designation EMAC2707, and DS-1130 (Chevron), and n-butyl acrylates ("ENBA") (QuantumChemical) were found to be acceptable copolymers. Ethylene copolymerssuch as the acrylic and methacrylic acid copolymers and their partiallyneutralized salts and ionomers, such as PRIMACOR® (Dow Chemical Company)and SURYLN® (E.I. DuPont de Nemours & Company) were also acceptable.Typically, ethylene based copolymers have melting point temperatures ofless than about 110° C. are not suited for autoclaving at 121° C.applications. Furthermore, only a limited range of proportions of eachcomponent allows the simultaneous fulfillment of the flexibility andautoclavability requirements.

Preferably the first component is chosen from the group of polypropylenehomo and random copolymers with alpha olefins which constitutesapproximately 30-60%, more preferably 35-45%, and most preferably 45%,by weight of the film. For example, random copolymers of propylene andethylene where the ethylene content is in an amount within the range of0-6%, and more preferably within the range of 2-6%, of the weight of thepropylene is preferred as the first component.

The second component of the RF layer 14 confers flexibility and lowtemperature ductility to the RF layer 14 and is chosen from the groupconsisting of polyolefins that do not have propylene repeating units("non propylene based polyolefins") including ethylene copolymersincluding ULDPE, polybutene, butene ethylene copolymers, ethylene vinylacetate, copolymers with vinyl acetate contents between approximately18-50%, ethylene methyl acrylate copolymers with methyl acrylatecontents being between approximately 20-40%, ethylene n-butyl acrylatecopolymers with n-butyl acrylate content of between 20-40%, ethyleneacrylic acid copolymers with the acrylic acid content of greater thanapproximately 15%. An example of these products are sold under suchproduct designations as TAFMER A-4085 (Mitsui), EMAC DS-1130 (Chevron),EXACT 4023, 4024 and 4028 (Exxon). Preferably, the second component iseither ULDPE sold by Mitsui Petrochemical Company under the designationTAFMER A-4085, or polybutene-1, PB8010 and PB8310 (Shell Chemical Co.),and should constitute approximately 25-50%, more preferably 35-45%, andmost preferably 45%, by weight of the film.

The first and second components of the RF layer 14 may be replaced by asingle component selected from a high melting temperature and flexibleolefins such as those polypropylenes sold by the Rexene Company underthe product designation FPO. The melting point temperature of thiscomponent should be greater than 130° C. and the modulus less than20,000 psi. This component should constitute between 30-60% by weight ofthe RF layer.

To impart RF dielectric loss to the RF layer 14, certain known highdielectric loss ingredients are included as the third component of thefilm structure 10. For example, EVA and EMA of sufficiently highco-monomer contents exhibit significant loss properties at 27 MHz toallow the compositions to be sealed by the dielectric process.Polyamides as a class of material, and ethylene vinyl alcohol ("EVOH")copolymers (typically produced by hydrolysing EVA copolymers), bothpossess high dielectric loss properties at suitable temperatures. Otheractive materials include PVC, vinylidine chlorides, and fluorides,copolymer of bis-phenol-A and epichlorohydrines known as PHENOXYS®(Union Carbide). However, significant contents of these chlorine andfluorine containing polymers would make them environmentally unsound asincineration of such a material would generate inorganic acids.Therefore, the third component of the RF layer 14 is preferably chosenfrom the class of polyamides.

Preferably, the polyamides of the present invention will be chosen fromaliphatic polyamides resulting from the condensation reaction ofdi-amines having a carbon number within a range of 2-13, aliphaticpolyamides resulting from a condensation reaction of di-acids having acarbon number within a range of 2-13, polyamides resulting from thecondensation reaction of dimer fatty acids, and amide containingcopolymers (random, block or graft).

Polyamides such as nylons are widely used in film material because theyoffer abrasion resistance to the film. However, rarely are the nylonsfound in the layer which contacts medical solutions as they typicallycontaminate the solution by leaching out into the solution. However, ithas been found by the applicants of the present invention that variousdimer fatty acid polyamides sold by, for example, Henkel Corporationunder the product designations MACROMELT and VERSAMID do not lead tosuch contamination and thus are the most preferred third component ofthe RF layer 14. The third component should constitute approximately3-40%, more preferably between 7-13%, and most preferably 10%, by weightof the RF layer 14.

The fourth component of the RF layer 14 confers compatibility betweenthe polar and nonpolar components of the RF layer 14. The fourthcomponent was chosen from styrene-hydrocarbon block copolymers andpreferably SEBS block copolymers that are modified by maleic anhydride,epoxy, or carboxylate functionalities. Most preferably the fourthcomponent is an SEBS block copolymer that is maleic anhydridefunctionalized. Such a product is sold by Shell Chemical Company underproduct designation KRATON RP-6509. The fourth component shouldconstitute approximately 5-40%, more preferably 7-13%, and mostpreferably 10% by weight of the RF layer 14.

It may also be desirable to include a fifth component to the RF layer 14of an SEBS block copolymer, not modified by the above functional groups,such as the one sold by the Shell Chemical Company under the productdesignation KRATON G-1652. This component should constitute between5-40% by weight of the RF layer, more preferably between 7-13%, and mostpreferably 10%.

Preferably the RF susceptible layer will have a thickness within therange of 1-9 mils are more preferably 5.0 mils-8.0 mils, and mostpreferably 5.0 mils. The skin layer will have a thickness within therange of 0.2-3.0 mils and most preferably 0.5 mils.

FIG. 2 shows another embodiment of the present invention having a corelayer 16 interposed between the skin layer 12 and the RF layer 14. Thecore layer 16 confers heat distortion resistance, and flexibility to thefilm structure 10 and compatibility among the components of the filmstructure 10. Preferably, the core layer will have a thickness withinthe range of 0.5-10 mils and more preferably 1-4 mils. The core layer 16includes three components. The first component is a polyolefin andpreferably a polypropylene in an amount that constitutes in a range of20-60% by weight of the core layer 16, more preferably 35-50%, and mostpreferably 45% of the core layer 16.

The second component of the core layer 16 is chosen from a groupconsisting of compounds that confer flexibility to the core layer 16including ULDPE, and polybutene copolymers. Preferably, the secondcomponent of the core layer is ULDPE or polybutene-1 in an amount byweight of 40%-60%, more preferably 40-50%, and most preferably 40%.

The third component of the core layer 16 is chosen from a group ofcompounds that confer compatibility among the components of the corelayer 16 and includes styrene-hydrocarbon block copolymers and mostpreferably SEBS block copolymers. The third component is in an amountpreferably within a range of 5-40% by weight of the core layer 16, morepreferably 7-15%, and most preferably 15%.

It is also possible to add as a fourth component of the core layer 16,reground trim scrap material recovered during the manufacturing ofcontainers. The scrap material is dispersed throughout the core layer16. Scrap may be added in an amount preferably between approximately0-50% by weight of the core layer 16, and more preferably within therange of 10-30% and most preferably within the range of 3-12%.

FIG. 3 shows the film or structure of FIG. 1 including a solutioncontact layer 17 adhered to a side of the RF layer opposite the skinlayer 12. The solution contact layer 17 includes three components thatmay be chosen from the same first three components and the same weightpercentage ranges of the core layer 16 set forth above. Preferably, thesolution contact layer 17 has a thickness within the range of 0.2-1.0mils and most preferably 1.0 mils.

FIG. 4 shows another embodiment of the multiple layer film structurehaving the skin layer 12, core layer 16, and RF layer 14 as describedabove with an additional discrete layer of scrap 20 between the skinlayer 12 and the core layer 16. FIG. 5 shows the discrete scrap layer 20between the core layer 16 and the RF layer 20. FIG. 6 shows the scraplayer 20 dividing the core layer 16 into first and second core layers14a and 14b. Preferably, the layer of regrind should have a thicknesswithin the range of 0.5-5.0 mils and most preferably 1.0 mils.

FIG. 7 shows another embodiment of the present invention having sevenlayers including the skin 12, core 16, and RF layers 14 discussed above,with a barrier layer 26 interposed between the core 16 and RF layers 14and adhered thereto with tie layers 28 attached to opposite sides of thebarrier layer 26. FIG. 8 shows the barrier layer 26 between the corelayer 16 and the skin layer 12. FIG. 9 shows the barrier layer 26dividing the core layer 14 into two core layers 14a and 14b. The barrierlayer 26 increases the gas barrier properties of the film structure 10.The barrier layer 26 is selected from the group consisting ethylenevinyl alcohols such as that sold under the name EVALCA (EVALCA Co.),highly glassy or crystalline polyamide such as SCLAR PA® (DupontChemical Co.), high nitrile content acrylonitrile copolymers such asBarex® sold by British Petroleum. Preferably, the barrier layer 26 isethylene vinyl alcohol, and has a thickness within the range of 0.3-1.5mils and most preferably 1.0 mils.

The tie layers 28 may be selected from modified ethylene and propylenecopolymers such as those sold under the product designations PLEXAR(Quantum Chemical Co.) and BYNEL (Dupont) and should have a thicknesswithin the range of 0.2-1.0 mils and most preferably 0.5 mil.

The above layers may be processed by coextrusion, coextrusion coating,or other acceptable process. It should be understood; however, that themethod of manufacturing the film structure is not a part of the presentinvention, and thus the scope of this invention should not be limited tothis extent.

These materials may be used to manufacture I.V. therapy bags such as theone shown in FIG. 10 and generally designated as 30.

Films having various combinations of the above components and weightpercentages as set forth in the examples below were tested using thefollowing methods.

(1) AUTOCLAVABILITY:

Autoclave resistance is measured by sample creep, or the increase in thesample length, at 121° C. under 27 psi loading for one hour. Theautoclave resistance must be less than or equal to 60%. (2) LOW ANDAMBIENT TEMPERATURE DUCTILITY:

(A) Low Temperature Ductility

In an instrumented impact tester fitted with a low temperatureenvironmental chamber cooled with liquid nitrogen, film samples about 7by 7 inches (18 cm by 18 cm) are mounted onto circular sample holdersabout 6 inches (15 cm) in diameter. A semispherical impact head withstress sensors is driven at high velocities (typically about 3 m/sec)into the preconditioned film loading it at the center. Thestress-displacement curves are plotted, and the energy of impact iscalculated by integration. The temperature at which the impact energyrises dramatically, and when the fractured specimen changes from brittleto ductile, high strain morphology is taken as a measure of the lowtemperature performance of the film ("L.Temp").

(B) Mechanical Modulus and Recovery:

The autoclaved film sample with a known geometry is mounted on aservohydraulically driven mechanical tester having cross heads toelongate the sample. At 10 inches (25 cm) per minute crosshead speed,the sample is elongated to about 20% elongation. At this point, thecross-heads travel and then reverse to travel in a direction oppositethat originally used to stretch the sample. The stress strain behavioris recorded on a digital recorder. The elastic modulus ("E(Kp-si)") istaken from the initial slope on the stress-strain curve, and therecovery taken from the excess sample dimension as a percentage ofsample elongation.

(3) RF PROCESSIBILITY:

Connected to a Callanan 27.12 MHz, 2 KW Radio Frequency generator, is arectangular brass die of about 0.25 (6.3 mm) by 4 inches (10 cm)opposing to a flat brass electrode, also connected to the generator.Upon closing the die with two sheets of the candidate material inbetween with solution sides facing each other, RF power of differentamplitudes and durations are applied. When the RF cycle is over, the dieis opened and the resultant seal examined by manually pulling apart thetwo sheets. The strength of the seal (versus the film strength) and themode of failure (peel, tear, or cohesive failures) are used to rate theRF responsiveness of the material.

Alternatively, the candidate film is first sputter coated with gold orpalladium to a thickness of 100 angstroms to render the surfaceconductive, cut into a circular geometry and mounted between theparallel electrodes in a dielectric capacitance measuring cell. Using aHewlett Packard 4092 automatic RF bridge, the dielectric constant andthe dielectric losses are measured at different frequencies up to 10 MHzand temperatures up to 150° C. The dielectric loss allows thecalculation of heat generation under an RF field. From calculations orcorrelations with RF seal experiments the minimum dielectric loss forperformance is obtained.

If the RF seal performance is obtained from the Callanan sealer, thefollowing ranking scale is adopted:

    ______________________________________                                        RF Power RF Time       Seal Strength                                                                           Rating                                       ______________________________________                                        80%      10            No        0                                            80%      10            Peelable  1                                            80%      05            Peelable  2                                            60%      03            Strong    3                                            50%      03            Strong    4                                            30%      03            Strong    5                                            ______________________________________                                    

(4) OPTICAL CLARITY:

Post autoclaved film samples are first cut into about 2 by 2 inches (5by 5 cms) squares, mounted on a Hunter Colorimeter and their internalhaze measured according to ASTM D-1003. Typically, internal haze levelof less than 30% is required, preferably less than 20% for thesethicknesses ("Haze %").

(5) STRAIN WHITENING:

The autoclaved film is strained at moderate speeds of about 20 inches(50 cm) per minute to about 100% elongation (twice the original length)and the presence of strain whitening (indicated by 1) or lack thereof(indicated by 0) is noted ("S.Whitening").

(6) ENVIRONMENTAL COMPATIBILITY:

The environmental compatibility comprises three important properties:(a) the material is free of low molecular weight plasticizers whichcould leach into landfills upon disposal, (2) the material can bethermoplastically recycled into useful items upon fulfilling the primarypurpose of medical delivery, and (3) when disposed of by energy reclaimby incineration, no significant inorganic acids are released to harm theenvironment. ("Envir."). The composition will also contain less than0.1% halogens by weight. In order to facilitate recycling by meltprocessing, the resultant composition should have a loss tangent greaterthan 1.0 at 1 Hz measured at processing temperatures.

(7) SOLUTION COMPATIBILITY

By solution compatibility we mean that a solution contained within thefilm is not contaminated by components which constitute the composition.("S.Comp.") The low molecular weight water soluble fraction of thecomposition will be less than 0.1%.

The following combinations were tested using the above test for thefilms set forth below.

    __________________________________________________________________________    Refer-                             Strain          Di- Low                    ence                                                                              Layer                     Modulus                                                                            Recovery                                                                           %  Environ-                                                                           Auto-                                                                            electric                                                                          Temp-                                                                             S.                 Number                                                                            Type                                                                              Layer Composition     (kpsi)                                                                             E(kpsi)                                                                            Haze                                                                             mental.                                                                            clav.                                                                            Loss                                                                              erature                                                                           Comp.              __________________________________________________________________________    FIG. 1                                                                            Skin                                                                              0.5 mil -                                                                          100% Amoco PP Copolymer                                                                        25   75   10 Yes  Yes                                                                              3   -35°                                                                       Yes                             8410                                                                 RF  8.0 mils -                                                                          40% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  10% Shell KRATON ™ RP-6509                                                 10% Henkel MACROMELT ™ 6301                                  FIG. 2                                                                            Skin                                                                              0.5 mil -                                                                          100% Amoco PP Copolymer                                                                        25   75   12 Yes  Yes                                                                              4   -40°                                                                       Yes                             8410                                                                 Core                                                                              4.0 mils -                                                                          45% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  15% Shell KRATON ™ G1657                                         RF  5.0 mils -                                                                          40% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  10% Shell KRATON ™ RP-6509                                                 10% Henkel MACROMELT ™ 6301                                  FIG. 3                                                                            Skin                                                                              0.5 mil -                                                                          100% Amoco PP Copolymer                                                                        25   70   15 Yes  Yes                                                                              2   -35°                                                                       Yes                             8410                                                                 RF  8.0 mils -                                                                          40% Solvay FORTILENE ™ PP                                                 Copolymer 8410                                                                 40% Mitsui TAFMER ™ ULDPE                                                  10% Shell KRATON ™ EP-6509                                                 10% Henkel MACROMELT ™ 6301                                      Solution                                                                          1.0 mils -                                                                          45% Solvay FORTILENE ™ PP                                        Contact  Copolymer 4208                                                       Skin      40% Mitsui TAFMER ™ ULDPE                                                  15% Shell KRATON ™ G1657                                     FIG. 4                                                                            Skin                                                                              0.5 mil -                                                                          100% Amoco PP Copolymer                                                                        25   75   16 Yes  Yes                                                                              4   -35°                                                                       Yes                             8410                                                                 Regrind                                                                           1.0 mil -                                                                          100% Regrind                                                         Core                                                                              3.0 mils -                                                                          45% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  15% Shell KRATON ™ G1657                                         RF  5.0 mils -                                                                          40% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  10% Shell KRATON ™ RP6509                                                  10% Henkel MACROMELT ™ 6301                                  FIG. 5                                                                            Skin                                                                              0.5 mil -                                                                          100% Amoco PP Copolymer                                                                        25   75   16 Yes  Yes                                                                              4    35°                                                                       Yes                             8410                                                                 Core                                                                              3.0 mils -                                                                          45% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  15% Shell KRATON ™ G1657                                         Regrind                                                                           1.0 mil -                                                                          100% Regrind                                                         RF  5.0 mils -                                                                          40% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  10% Shell KRATON ™ RP6509                                    FIG. 6                                                                            Skin                                                                              0.5 mil -                                                                          100% Amoco PP Copolymer                                                                        25   75   16 Yes  Yes                                                                              4   -35°                                                                       Yes                             8410                                                                 Core                                                                              1.5 mils -                                                                          45% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  15% Shell KRATON ™ G1657                                         Regrind                                                                           1.0 mil                                                                            100% Regrind                                                         Core                                                                              1.5 mils                                                                            45% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  15% Shell KRATON ™ G1657                                         RF  5.0 mils                                                                            45% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  15% Shell KRATON ™ RP6509                                                  10% Henkel MACROMELT ™ 6301                                  FIG. 7                                                                            Skin                                                                              0.5 mil -                                                                          100% Amoco PP Copolymer                                                                        30   20   20 Yes  Yes                                                                              4   -20°                                                                       Yes                             8410                                                                 Core                                                                              1.5 mils -                                                                          45% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  15% Shell KRATON ™ G1657                                         Tie 0.5 mil                                                                            100% BYNEL                                                           Barrier                                                                           1.0 mil                                                                            100% EVOH                                                            Tie 0.5 mil                                                                            100% BYNEL                                                           RF  5.0 mils                                                                            40% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  10% Shell KRATON ™ RP6509                                                  10% Henkel MACROMELT ™ 6301                                  FIG. 8                                                                            Skin                                                                              0.5 mil -                                                                          100% Amoco PP Copolymer                                                                        30   70   20 Yes  Yes                                                                              3   -20°                                                                       Yes                             8410                                                                 Tie 0.5 mil                                                                            100% BYNEL                                                           Barrier                                                                           1.0 mil                                                                            100% EVOH                                                            Tie 0.5 mil                                                                            100% BYNEL                                                           Core                                                                              2.0 mils -                                                                          45% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  15% Shell KRATON ™ G 1657                                        RF  5.0 mils                                                                            40% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  10% Shell KRATON ™ RP6509                                                  10% Henkel MACROMELT ™ 6301                                  FIG. 9                                                                            Skin                                                                              0.5 mil -                                                                          100% Amoco PP Copolymer                                                                        30   70   20 Yes  Yes                                                                              3   -20°                                                                       Yes                             8410                                                                 Core                                                                              1.0 mils -                                                                          45% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  15% Shell KRATON ™ G 1657                                        Tie 0.5 mil                                                                            100% BYNEL                                                           Barrier                                                                           1.0 mil                                                                            100% EVOH                                                            Tie 0.5 mil                                                                            100% BYNEL                                                           Core                                                                              1.0 mils -                                                                          45% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  15% Shell KRATON ™ G 1657                                        RF  5.0 mils                                                                            40% Solvay FORTILENE ™ PP                                                 Copolymer 4208                                                                 40% Mitsui TAFMER ™ ULDPE                                                  10% Shell KRATON ™ RP6509                                                  10% Henkel MACROMELT ™ 6301                                  __________________________________________________________________________

It will be understood that the invention may be embodied in otherspecific forms without departing from the spirit or centralcharacteristics thereof. The present examples and embodiments,therefore, are to be considered in all respects as illustrative and notrestrictive, and the invention is not to be limited to the details givenherein.

We claim:
 1. A multiple layer thermoplastic structure:(1) a skin layerselected from the group consisting of polypropylene and polypropylenecopolymers; (2) a radio frequency susceptible layer adhered to the skinlayer, the radio frequency susceptible layer having a dielectric lossgreater than 0.05 at 1-60 MHz and at temperatures of ambient to 250° C.,the radio frequency susceptible layer having:(a) a first polyolefinselected from the group consisting of polypropylene and polypropylenecopolymers, (b) a second polyolefin selected from the group consistingof ethylene copolymers, ultra-low density polyethylene, polybutene, andbutene ethylene copolymers; (c) a radio frequency susceptible polymerselected from the group consisting of polyamides, ethylene vinyl acetatewith a vinyl acetate comonomer content of 18-50% by weight, ethylenemethyl acrylate copolymers with methyl acrylate comonomer content from20%-40% by weight, ethylene vinyl alcohol with vinyl alcohol comonomercontent from 15%-70%; and (d) a compatibilizing agent of a styrene andhydrocarbon block copolymer;wherein the structure has physicalproperties within the range a<40,000 psi; b>=70%; c<30w; d>1.0; e<0.1%;f<0.1%; g>=0.05; h<=60%; i=0;wherein: a is the mechanical modulus of thecomposition measured according to ASTM D-882; b is the percent recoveryin length of the composition after an initial 20% deformation; c is theoptical haze of the composition processed into a film 9 mils inthickness measured in accordance to ASTM D-1003; d is the loss tangentof the composition at 1 Hz measured at melt processing temperatures; eis the elemental halogen content by weight of the composition; f is thelow molecular weight water soluble fraction of the composition; g is thedielectric loss between 1 and 60 MHz and over temperatures of 25 to 250°C. of the composition; h is the sample creep measured at 121° C. for asample strip of the composition under 27 psi loading; and, i thecomposition exhibits no strain whitening after being strained atmoderate speeds of about 20 inches per minute to about twice theoriginal length;and wherein the multiple layer structure is capable ofstoring or collecting beneficial agents or transferring such agents to apatient, and wherein the multiple layer structure is capable of beingthermoplastically recycled.
 2. A multiple layer thermoplastic structuresuitable for manufacturing medical products comprising:(1) a skin layerselected from the group consisting of polypropylene and polypropylenecopolymers; and, (2) a radio frequency susceptible layer adhered to theskin layer, the radio frequency susceptible layer having a dielectricloss greater than 0.05 at 1-60 MHz and at temperatures of ambient to250° C., the radio frequency susceptible layer comprising:(a) a firstpolyolefin selected from the group consisting of polypropylene andpolypropylene copolymers; (b) a second polyolefin selected from thegroup consisting of ethylene copolymers, ultra-low density polyethylene,polybutene, and butene ethylene copolymers; (c) a radio frequencysusceptible polymer selected from the group consisting of polyamides,ethylene vinyl acetate copolymers with a vinyl acetate comonomer contentfrom 18-50% by weight, ethylene methyl acrylate copolymers with methylacrylate comonomer content from 20%-40% by weight, ethylene vinylalcohol with vinyl alcohol comonomer content from 15%-70% by molepercent; and(d) a first compatibilizing agent of a styrene andhydrocarbon block copolymer; wherein the multiple layer structure has amechanical modulus of less than 40,000 psi when measured according toASTM D-882, the optical haze of the structure processed into a film 9mils in thickness measured in accordance to ASTM D-1003 is less than30%, the structure exhibits no strain whitening after being strained atmoderate speeds of about 20 inches per minute to about twice theoriginal length and the structure is capable of storing or collectingbeneficial agents or transferring such agents to a patient, thestructure has a sample creep measured at 121° C. for a sample strip ofthe structure under 27 psi loading of less than or equal to 60%, andwherein the multiple layer structure is capable of beingthermoplastically recycled.
 3. The structure of claim 2 wherein thepolyamide is selected from a group consisting of: aliphatic polyamidesresulting from the condensation reaction of di-amines having a carbonnumber within a range of 2-13, aliphatic polyamides resulting from acondensation reaction of di-acids having a carbon number within a rangeof 2-13, polyamides resulting from the condensation reaction of dimerfatty acids, and amide containing copolymers.
 4. The structure of claim2 wherein the styrene and hydrocarbon block copolymer is selected from agroup consisting of a first styrene-ethylene-butene-styrene blockcopolymer, and a maleic anhydride functionalized block copolymer.
 5. Thestructure of claim 2 further comprising:(1) a first core layerhaving:(a) a third polyolefin selected from the group consisting ofpolypropylene and polypropylene copolymers, (b) a fourth polyolefinselected from the group consisting of ultra low density polyethylene,and polybutene-1 copolymers; and (c) a second compatibilizing agent of astyrene and hydrocarbon block copolymer; (2) a beneficial agent contactlayer attached to the radio frequency susceptible layer on a sideopposite the skin layer, the contact layer comprises:(a) apolypropylene, (b) an ultra low density polyethylene, and, (c) a thirdstyrene and hydrocarbon block copolymer; (3) a first scrap layercomprising a first scrap material; (4) a first barrier layer; andwhereinthe first core layer, first scrap layer and first barrier layer areattached together in any order and are interposed between the skin layerand the susceptible layer.
 6. The structure of claim 5 wherein the firstcore layer further includes a second scrap material.
 7. The structure ofclaim 5 further including a second scrap layer comprising a second scrapmaterial interposed between the first core layer and the radio frequencysusceptible layer.
 8. A multiple layer thermoplastic structure suitablefor manufacturing medical products, the structure comprising:(1) a skinlayer from the group consisting of polypropylene and polypropylenecopolymers; and, (2) a radio frequency susceptible layer adhered to theskin layer, the radio frequency susceptible layer having a dielectricloss greater than 0.05 at 1-60 MHz and at temperatures of ambient to250° C. and comprising:(a) a first polyolefin in an amount in a range of30-60% by weight of the radio frequency susceptible layer and selectedfrom the group consisting of polypropylene and polypropylene copolymers,(b) a second polyolefin in an amount within the range of 25-50% byweight of the radio frequency susceptible layer selected from the groupconsisting of ethylene copolymers, ultra-low density polyethylene,polybutene, and butene ethylene copolymers; (c) a radio frequencysusceptible polymer in an amount within the range of 3-40% by weight ofthe radio frequency susceptible layer selected from the group consistingof polyamides, ethylene vinyl acetate with vinyl acetate comonomercontents from 18-50% by weight, ethylene methyl acrylate copolymers withmethyl acrylate comonomer contents from 20%-40% by weight, ethylenevinyl alcohol with vinyl alcohol comonomer contents from 15%-70% by molepercent, and (d) a compatibilizing agent of a styrene and hydrocarbonblock copolymer in an amount within the range of 5-40% by weight of theradio frequency susceptible layer, andwherein the multiple layerstructure has a mechanical modulus of less than 40,000 psi when measuredaccording to ASTM D-882, the optical haze of the structure processedinto a film 9 mils in thickness measured in accordance to ASTM D-1003 isless than 30%, the structure exhibits no strain whitening after beingstrained at moderate speeds of about 20 inches per minute to about twicethe original length and the structure is capable of storing orcollecting beneficial agents or transferring such agents to a patient,the structure has a sample creep measured at 121° C. for a sample stripof the structure under 27 psi loading of less than or equal to 60%, andwherein the multiple layer structure is capable of beingthermoplastically recycled.
 9. The structure of claim 8 wherein theradio frequency susceptible polymer is a fatty acid polyamide.
 10. Thestructure of claim 8 wherein the compatibilizing agent is astyrene-ethylene-butene-styrene block copolymer.
 11. The structure ofclaim 10 wherein the compatibilizing agent comprises astyrene-ethylene-butene-styrene block copolymer that is maleic anhydridefunctionalized.
 12. The structure of claim 11 wherein the radiofrequency susceptible layer comprises:35-45% polypropylene; 35-45%second polyolefin; 7-13% fatty acid polyamide; and, 7-13% maleicanhydride functionalized styrene-ethylene-butene-styrene blockcopolymer.
 13. The structure of claim 12 wherein the fatty acidpolyamide is a dimer fatty acid polyamide.
 14. A multiple layerthermoplastic structure suitable for fabricating medical productscomprising:a skin layer selected from the group consisting of apolypropylene and polypropylene copolymers; a core layer having a firstside adhered to the skin layer and a second side; and, a radio frequencysusceptible layer having a first side adhered to the second side of thecore layer comprising:a first polyolefin selected from the groupconsisting of a polypropylene and polypropylene copolymers in an amountfrom 30-60% of the weight of the radio frequency susceptible layer; asecond polyolefin in an amount from 25-50% of the weight of the radiofrequency susceptible layer and selected from the group consisting ofethylene copolymers, ultra-low density polyethylene, polybutene, buteneethylene copolymers, ethylene copolymers with vinyl acetate having from18-50% by weight vinyl acetate comonomer, ethylene methyl acrylatecopolymers with methyl acrylate contents being from 20-40% by weight,ethylene n-butyl acrylate copolymers with n-butyl acrylate content from20-40% by weight, ethylene acrylic acid copolymers with the acrylic acidcontent of greater than approximately 15% by weight; a radio frequencysusceptible polymer in an amount within the range of 3-40% by weight ofthe radio frequency susceptible layer and selected from the groupconsisting of polyamides, ethylene vinyl acetate with a vinyl acetatecontent in an amount of 18-50% by weight, ethylene methyl acrylatecopolymers with methyl acrylate in an amount from 20%-40% by weight,ethylene vinyl alcohol with vinyl alcohol in an amount from 15%-70%; anda first compatibilizing agent in an amount within the range of 5-40% byweight of the radio frequency susceptible layer and of a styrene andhydrocarbon block copolymer,and wherein the multiple layer structure hasa mechanical modulus of less than 40,000 psi when measured according toASTM D-882, the optical haze of the structure processed into a film 9mils in thickness measured in accordance to ASTM D-1003 is less than30%, the structure exhibits no strain whitening after being strained atmoderate speeds of about 20 inches per minute to about twice theoriginal length and the structure is capable of storing or collectingbeneficial agents or transferring such agents to a patient, thestructure has a sample creep measured at 121° C. for a sample strip ofthe structure under 27 psi loading of less than or equal to 60%, andwherein the multiple layer structure is capable of beingthermoplastically recycled.
 15. The structure of claim 14 wherein thecore layer has a dielectric loss equal to or less than 0.05 at 1-60 MHzand at temperatures of ambient to 250° C.
 16. The structure of claim 15wherein the second polyolefin is selected from the group consisting ofultra low density polyethylene and polybutene-1,wherein the radiofrequency susceptible polymer is a dimer fatty acid polyamide, whereinthe first compatibilizing agent is selected from the group consisting ofa styrene-ethylene-butene-styrene block copolymer, and astyrene-ethylene-butene-styrene block copolymer functionalized by afunctional group selected from the group consisting of a maleicanhydride, epoxy and carboxylate; and wherein the core layercomprises:(1) a third polyolefin selected from the group consisting ofpolypropylene and polypropylene copolymers; (2) a fourth polyolefinselected from the group consisting of an ultra low density polyethyleneand a polybutene copolymer; and (3) a second compatibilizing agent of astyrene and hydrocarbon block copolymer.
 17. The structure of claim 16wherein the core layer further includes a scrap material.
 18. A multiplelayer thermoplastic structure of stacked layers suitable formanufacturing medical products comprising:(1) a skin layer having afirst side and being selected from a group consisting of a polypropyleneand polypropylene copolymers; (2) a radio frequency susceptible layerhaving second and third sides, the radio frequency susceptible layercomprising(a) a polypropylene in an amount from 30-60% of the weight ofthe radio frequency susceptible layer, (b) a first polyolefin in anamount from 25-50% of the weight of the radio frequency susceptiblelayer and selected from the group consisting of ethylene copolymers,ultralow density polyethylene, polybutene, butene ethylene copolymers,(c) a radio frequency susceptible polymer in an amount from 3-40% byweight of the radio frequency susceptible layer and selected from thegroup consisting of polyamides, ethylene vinyl acetate with a vinylacetate comonomer contents from 18-50% by weight, ethylene methylacrylate copolymers with methyl acrylate comonomer contents from 20%-40%by weight, ethylene vinyl alcohol with vinyl alcohol comonomer contentsfrom 15%-70% mole percent, (d) a first compatibilizing agent of astyrene and hydrocarbon block copolymer in an amount from 5-40% byweight of the radio frequency susceptible layer; and (e) wherein theradio frequency susceptible layer having a dielectric loss greater than0.05 at 1-60 MHz and at temperatures of ambient to 250° C.; (3) a firstcore layer having fourth and fifth sides; (4) scrap layer having sixthand seventh sides; andwherein the multiple layer structure has amechanical modulus of less than 40,000 psi when measured according toASTM D-882, the optical haze of the structure processed into a film 9mils in thickness measured in accordance to ASTM D-1 003 is less than30%, the structure exhibits no strain whitening after being strained atmoderate speeds of about 20 inches per minute to about twice theoriginal length and the structure is capable of storing or collectingbeneficial agents or transferring such agents to a patient, thestructure has a sample creep measured at 121° C. for a sample strip ofthe structure under 27 psi loading of less than or equal to 60%, andwherein the multiple layer structure is capable of beingthermoplastically recycled.
 19. The structure of claim 18 wherein thefirst side is adjacent to the fourth side, the sixth side is adjacent tothe fifth side, and the second side is adjacent to the seventh side. 20.The structure of claim 18 wherein the first side is adjacent to thesixth side, the fourth side is adjacent to the seventh side, and thesecond side is adjacent to the fifth side.
 21. The structure of claim 20further including a second core layer interposed between the first corelayer and the radio frequency susceptible layer.
 22. The structure ofclaim 18 wherein the first polyolefin is selected from the groupconsisting of an ultra low density polyethylene and polybutene-1, theradio frequency susceptible polymer is a dimer fatty acid polyamide, thefirst compatibilizing agent is styrene-ethylene-butene-styrene blockcopolymer, and the first core layer comprises:(1) a second polyolefinselected from the group consisting of polypropylene and polypropylenecopolymers; (2) a third polyolefin selected from the group consisting ofan ultra low density polyethylene and a polybutene copolymer; and, (3) asecond compatibilizing agent of a styrene and hydrocarbon blockcopolymer.
 23. A multiple layer thermoplastic structure suitable formanufacturing medical products comprising:(1) a skin layer having afirst side and being selected from a group consisting of a polypropyleneand polypropylene copolymers; (2) a radio frequency susceptible layerhaving sixth and seventh sides and comprising:(a) a propylene-containingpolymer in an amount in a range of 30-60% of the weight of the radiofrequency susceptible layer, (b) a first polyolefin in an amount withinthe range of 25-50% of the weight of the radio frequency susceptiblelayer and selected from the group consisting of ethylene copolymers,ultra-low density polyethylene, polybutene, butene ethylene copolymers;(c) a radio frequency susceptible polymer in an amount within the rangeof 3-40% by weight of the radio frequency susceptible layer and selectedfrom the group consisting of polyamides, ethylene vinyl acetate with avinyl acetate content in an amount from 18-50% by weight, ethylenemethyl acrylate copolymers with methyl acrylate comonomer contents from20%-40% by weight, ethylene vinyl alcohol with vinyl alcohol in anamount from 15%-70% mole percent, (d) a compatibilizing agent of astyrene and hydrocarbon block copolymer in an amount within the range of5-40% by weight of the radio frequency susceptible layer; and (e)wherein the radio frequency susceptible layer having a dielectric lossgreater than 0.05 at 1-60 MHz and at temperatures of ambient to 250° C.;(3) a first core layer having fourth and fifth sides and disposedbetween the skin layer and the radio frequency susceptible layer; (4) abarrier layer having second and third sides adjacent to the core layer,and wherein the multiple layer structure has a mechanical modulus ofless than 40,000 psi when measured according to ASTM D-882, the opticalhaze of the structure processed into a film 9 mils in thickness measuredin accordance to ASTM D-1003 is less than 30%, the structure exhibits nostrain whitening after being strained at moderate speeds of about 20inches per minute to about twice the original length and the structureis capable of storing or collecting beneficial agents or transferringsuch agents to a patient, the structure has a sample creep measured at121° C. for a sample strip of the structure under 27 psi loading of lessthan or equal to 60%, and wherein the multiple layer structure iscapable of being thermoplastically recycled.
 24. The structure of claim23 wherein the first side is adjacent to the second side, the fourthside is adjacent to the third side, and the sixth side is adjacent tothe fifth side.
 25. The structure of claim 24 further including a secondcore layer interposed between the first core layer and the radiofrequency susceptible layer.
 26. The structure of claim 23 wherein thefirst side is adjacent to the fourth side, the second side is adjacentto the fifth side, and the sixth side is adjacent to the third side. 27.The structure of claim 23 wherein the first polyolefin is ultra lowdensity polyethylene or polybutene-1, the radio frequency susceptiblepolymer is a dimer fatty acid polyamide, the compatibilizing agent is astyrene-ethylene-butene-styrene block copolymer, and wherein the barrierlayer includes an ethylene vinyl alcohol or a polyamide.
 28. Thestructure of claim 23 further including a first tie layer adjacent tothe second side of the barrier layer and a second tie layer adjacent tothe third side of the barrier layer.
 29. The structure of claim 28wherein the first and second tie layers comprise ethylene and propylenecopolymers.
 30. A multiple layer thermoplastic structure suitable formanufacturing medical products comprising:(1) a skin layer comprising apolypropylene copolymer and a styrene and hydrocarbon block copolymerwithin a range of 0-20% by weight of the skin layer; (2) a core layeradhered to the skin layer; and, (3) a radio frequency susceptible layeradhered to the core layer comprising:(a) a polypropylene having amelting point temperature greater than 130° C. and a modulus less than20,000 psi in an amount in a range of 30-60% of the weight of the radiofrequency susceptible layer, (b) a radio frequency susceptible polymerin an amount within the range of 3-40% by weight of the radio frequencysusceptible layer and is a dimer fatty acid polyamide; (c) a firstcompatibilizing agent of a styrene and hydrocarbon block copolymer in anamount within the range of 5-20% by weight of the radio frequencysusceptible layer, and (d) wherein the radio frequency susceptible layerhaving a dielectric loss greater than 0.05 at 1-60 MHz and attemperatures of ambient to 250° C.;wherein the multiple layer structurehas a mechanical modulus of less than 40,000 psi when measured accordingto ASTM D-882, the optical haze of the structure processed into a film 9mils in thickness measured in accordance to ASTM D-1003 is less than30%, the structure exhibits no strain whitening after being strained atmoderate speeds of about 20 inches per minute to about twice theoriginal length and the structure is capable of storing or collectingbeneficial agents or transferring such agents to a patient, and whereinthe multiple layer structure is capable of being thermoplasticallyrecycled.
 31. The structure of claim 30 wherein the core layercomprises:(a) a polyolefin selected from the group consisting ofpolypropylene and polypropylene copolymers; (b) a second componentselected from the group consisting of an ultra low density polyethyleneand a polybutene-1 copolymer; and (c) a second compatibilizing agent ofa styrene and hydrocarbon block copolymer.
 32. A multiple layerthermoplastic structure suitable for manufacturing medical productscomprising:(1) a skin layer selected from the group consisting ofpolypropylene and polypropylene copolymers; and, (2) a radio frequencysusceptible layer adhered to the skin layer, the radio frequencysusceptible layer having a dielectric loss greater than 0.05 at 1-60 MHzand at temperatures of ambient to 250° C., the radio frequencysusceptible layer comprising:(a) a first polyolefin selected from thegroup consisting of polypropylene and polypropylene copolymers; (b) asecond polyolefin selected from the group consisting of ultra-lowdensity polyethylene, polybutene, and butene ethylene copolymers; (c) aradio frequency susceptible polymer selected from the group consistingof polyamides and ethylene vinyl acetate copolymers with a vinyl acetatecomonomer content from 18-50% by weight; and (d) a first compatibilizingagent of a styrene and hydrocarbon block copolymer;wherein the multiplelayer structure has a mechanical modulus of less than 40,000 psi whenmeasured according to ASTM D-882, the optical haze of the structureprocessed into a film 9 mils in thickness measured in accordance to ASTMD-1 003 is less than 3 0%, the structure exhibits no strain whiteningafter being strained at moderate speeds of about 20 inches per minute toabout twice the original length and the structure is capable of storingor collecting beneficial agents or transferring such agents to apatient, the structure has a sample creep measured at 121° C. for asample strip of the structure under 27 psi loading of less than or equalto 60%, and wherein the multiple layer structure is capable of beingthermoplastically recycled.
 33. A multiple layer thermoplastic structuresuitable for manufacturing medical products comprising:(1) a skin layercomprising a polypropylene copolymer and a styrene and hydrocarbon blockcopolymer within a range of 0-20% by weight of the skin layer; (2) aradio frequency susceptible layer adhered to the skin layercomprising:(a) a polypropylene having a melting point temperaturegreater than 130° C. and a modulus less than 20,000 psi in an amount ina range of 30-60% of the weight of the radio frequency susceptiblelayer, (b) a radio frequency susceptible polymer in an amount within therange of 3-40% by weight of the radio frequency susceptible layer andselected from the group consisting of polyamides and ethylene vinylacetate with vinyl acetate comonomer contents in an amount of 18-50% byweight; (c) a first compatibilizing agent of a styrene and hydrocarbonblock copolymer in an amount within the range of 5-20% by weight of theradio frequency susceptible layer, and (d) wherein the radio frequencysusceptible layer having a dielectric loss greater than 0.05 at 1-60 MHzand at temperatures of ambient to 250° C.; and (3) wherein the multiplelayer structure has a mechanical modulus of less than 40,000 psi whenmeasured according to ASTM D-882, the optical haze of the structureprocessed into a film 9 mils in thickness measured in accordance to ASTMD-1003 is less than 30%, the structure exhibits no strain whiteningafter being strained at moderate speeds of about 20 inches per minute toabout twice the original length and the structure is capable of storingor collecting beneficial agents or transferring such agents to apatient, the structure has a sample creep measured at 121 ° C. for asample strip of the structure under 27 psi loading of less than or equalto 60%, and wherein the multiple layer structure is capable of beingthermoplastically recycled.
 34. A multiple layer thermoplastic structuresuitable for manufacturing medical products comprising:(1) a skin layerselected from the group consisting of polypropylene and polypropylenecopolymers; and, (2) a radio frequency susceptible layer adhered to theskin layer, the radio frequency susceptible layer having a dielectricloss greater than 0.05 at 1-60 MHz and at temperatures of ambient to250° C., the radio frequency susceptible layer comprising:(a) a firstpolyolefin selected from the group consisting of polypropylene andpolypropylene copolymers; (b) a second polyolefin selected from thegroup consisting of ultra-low density polyethylene, polybutene, andbutene ethylene copolymers; (c) a radio frequency susceptible polymer ofa polyamide; and (d) a first compatibilizing agent of a styrene andhydrocarbon block copolymer;wherein the multiple layer structure has amechanical modulus of less than 40,000 psi when measured according toASTM D-882, the optical haze of the structure processed into a film 9mils in thickness measured in accordance to ASTM D-1003 is less than30%, the structure exhibits no strain whitening after being strained atmoderate speeds of about 20 inches per minute to about twice theoriginal length and the structure is capable of storing or collectingbeneficial agents or transferring such agents to a patient, thestructure has a sample creep measured at 121° C. for a sample strip ofthe structure under 27 psi loading of less than or equal to 60%, andwherein the multiple layer structure is capable of beingthermoplastically recycled.
 35. The structure of claim 34 wherein thepolyamide is selected from a group consisting of: aliphatic polyamidesresulting from the condensation reaction of di-amines having a carbonnumber within a range of 2-13, aliphatic polyamides resulting from acondensation reaction of di-acids having a carbon number within a rangeof 2-13, polyamides resulting from the condensation reaction of dimerfatty acids, and amide containing copolymers.
 36. The structure of claim34 wherein the styrene and hydrocarbon block copolymer is selected froma group consisting of a first styrene-ethylene-butene-styrene blockcopolymer and a maleic anhydride functionalized block copolymer.
 37. Thestructure of claim 34 further comprising:a first core layer disposedbetween the skin layer and the radio frequency susceptible layer, thefirst core layer having:(a) a third polyolefin selected from the groupconsisting of polypropylene and polypropylene copolymers, (b) a fourthpolyolefin selected from the group consisting of ultra low densitypolyethylene, and polybutene-1 copolymers; and (c) a secondcompatibilizing agent of a styrene and hydrocarbon block copolymer. 38.The structure of claim 37 wherein the second compatiblizing agent is astyrene-ethylene-butene-styrene block copolymer.
 39. The structure ofclaim 37 wherein:(1) the first polyolefin is in an amount from 30-60% byweight of the radio frequency susceptible layer, (2) the secondpolyolefin is in an amount from 25-50% by weight of the radio frequencysusceptible layer, (3) the radio frequency susceptible polymer is in anamount from 3-40% by weight of the radio frequency susceptible layer,and (4) the compatibilizer polymer is in an amount from 5-40% by weightof the susceptible layer.
 40. The structure of claim 39 wherein:(1) thethird polyolefin is present in an amount from 20-60% of the core layer,(2) the fourth polyolefin is present in an amount from 40-60% by weightof the core layer; and (3) the compatiblizer is present in an amountfrom 5-40% by weight of the core layer.